Abstract
Abstract We propose an ultrafast all-optical anomalous Hall effect in two-dimensional (2D) semiconductors of hexagonal symmetry such as gapped graphene (GG), transition metal dichalcogenides (TMDCs), and hexagonal boron nitride (h-BN). To induce such an effect, the material is subjected to a sequence of two strong-field single-optical-cycle pulses: A chiral pump pulse followed within a few femtoseconds by a probe pulse linearly polarized in the armchair direction of the 2D lattice. Due to the effect of topological resonance, the first (pump) pulse induces a large chirality (valley polarization) in the system, while the second pulse generates a femtosecond pulse of the anomalous Hall current. The proposed effect is fundamentally the fastest all-optical anomalous Hall effect possible in nature. It can be applied to ultrafast all-optical storage and processing of information, both classical and quantum.
Highlights
Two-dimensional (2D) materials with honeycomb crystal structure [1], such as graphene, silicene, transition metal dichalcogenides (TMDCs), and hexagonal boron nitride (h-BN), possess nontrivial topological properties in the reciprocal space [2]
We propose an ultrafast all-optical anomalous Hall effect in two-dimensional (2D) semiconductors of hexagonal symmetry such as gapped graphene (GG), transition metal dichalcogenides (TMDCs), and hexagonal boron nitride (h-BN)
A gigantic ultrafast all-optical anomalous Hall effect occurs when two strong single-oscillation optical pulses are applied to the GG or similar hexagonal-symmetry semiconductor materials such as TMDCs or h-BN
Summary
Two-dimensional (2D) materials with honeycomb crystal structure [1], such as graphene, silicene, transition metal dichalcogenides (TMDCs), and hexagonal boron nitride (h-BN), possess nontrivial topological properties in the reciprocal space [2]. Such anomalous Hall effect can be realized, for example, in TMDC monolayers with unbalanced population of photoexcited valleys [16, 17] or in semiconductor systems with photoinduced spin polarization and strong spin–orbit interaction [18] In these systems, even without magnetic field, the time reversal symmetry is broken and under an applied DC electric field, the Hall current is generated. The GG can serve as a generic model of TMDCs. We predict the generation of an anomalous Hall current by a combination of a strong chiral pulse, which breaks the time-reversal symmetry playing the role of an effective magnetic field, followed by a linearly polarized probe pulse. Using the model of GG allows one to model materials with different bandgaps and to study how the anomalous Hall effect depends on the magnitude of the bandgap
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
